Separators are generally known in the art. Separators are used in rechargeable batteries in order to electrically isolate electrodes of opposite polarity from one another. These separators, or primary separators, are typically provided about the positive electrode or plate. This allows an ionically conductive path to be formed between the two electrodes, for example via electrolyte.
Separators are often manufactured to form a pocket which is open at the top. To form the pocket, a separator is typically folded. In some separators, the edges of the folded separator may then be connected, for example welded to one another, forming the pocket which is open at the top. To account for formation of the pocket, the separator is typically manufactured to have a length which is greater than the height of two separators.
While separators are generally known, separators have different performance requirements depending upon the end use of the rechargeable battery. For example, separators of a rechargeable battery employed in a lower cycling application, such as an automobile, may have different performance requirements than separators of a rechargeable battery employed in a high cycling application, such as in a smaller, lightweight vehicle, for example a golf car. The performance requirements are often related to separator life and/or performance.
Known separators for high cycling rechargeable batteries have various drawbacks. Among other drawbacks, known separators do not form or maintain effective acid conduits for cycling. Moreover, in electrode assemblies for high cycling batteries, the separator is often a leaf separator placed around the positive electrode. In addition, when a glass mat is used, the glass mat must face the positive plate, as it will embed itself during the life of the battery. Accordingly, the glass mat is added prior to placement of the positive electrode inside of the separator. The features of a leaf separator often present the problem of developing shorts around the separator as the plates are not fully enclosed, while enveloped separators can present problems related to acid stratification, which causes differences in acid concentrations between the top of the electrodes and the bottom of the electrodes. Therefore, a need exists for an improved electrode assembly and separator.